Recently, there has been desired to develop actuators for obtaining rotating operation and translating operation in a very small space. Such an actuator has been required to achieve further weight reduction.
FIGS. 7A to 7C illustrate a PZT tubular motor 50 developed by Tokyo University and IMRE (refer to Non-Patent Document 1). As illustrated in a plan view (FIG. 7C), a stator (PZT tube) 56 has four electrodes formed on an outer side surface thereof and polarized in a radial direction. When a sine voltage and a cosine voltage are applied as illustrated in FIG. 7C, a rotation flexure mode is excited (FIGS. 7A, 7B). FIG. 7A illustrates the tubular motor 50 in the case where the rotation flexure mode is excited, and FIG. 7E schematically illustrates operation in the rotation flexure mode. As illustrated in FIGS. 7A to 7C, two rotors 54a and 54b are capable of simultaneously rotating at two ends of the tubular motor 50, and the operation of the tubular motor 50 is very similar to that of an eccentric motor (see FIG. 7B).